Abstract: Objective: To understand the co-infection of syphilis and human immunodeficiency virus (HIV) and the risk factors among men who have sex with men (MSM) (who had temporary anal sex in the last 6 months) in Shenzhen. Methods: The samples were collected by snowball and respondent-driven sampling method. Chi-square test and multivariate logistic regression model were used to analyze the factors associated with co-infection of syphilis and HIV. Results: A total of 434 MSM were investigated. The infection rates of syphilis, HIV and co-infection of syphilis-HIV were 16.4%, 12.2%, and 7.3%, respectively. Multivariate logistic regression analysis showed that the older MSM (OR=4.0, P=0.0007), senior middle school level (OR=6.5, P=0.0081), playing exclusively receptive roles in anal sexual intercourse (OR=12.1, P=0.0017), having more anal sexual partners (OR=1.5, P=0.0455) and not always using condom in anal sexual intercourse in the past 6 months (OR=2.9, P=0.0236) were associated risk factors for syphilis and HIV co-infection. Conclusion: More efforts are needed to deal with the high co-infection of syilhilis and HIV in this population. 

Key words: Men who have sex with men, human immunodeficiency virus, syphilis